The research objectives include studying several aspects of transplantation immunology and lymphocyte biology. Specifically, the projects being pursued are concerned with: (1) analyzing in detail the behavior of the male specific antigen in rats; (2) studying the behavior of skin grafts incompatible with respect to skin specific (Sk) antigens, and (3) studying the behavior of histocompatibility antigen-activated cytotoxic T lymphocytes. In addition, we are also continuing to employ transplantation procedures to study the mode of action of specific coat-color determinants in mice. BIBLIOGRAPHIC REFERENCES: Silvers, W.K., G. Murphy and T.W. Poole. Studies on the H-Y antigen in rats. Immunogenetics 4:85-100, 1977. Silvers, W.K., and S.S. Wachtel. H-Y antigen: Behavior and Function. Science 195:956-960, 1977.